Bakkies Botha and Jean de Villiers were on Wednesday ruled out of the away leg of the Vodacom Tri Nations.
De Villiers has not recovered from the rib injury sustained against Scotland and is likely to miss the entire away leg, which comprises three tests against Australia (twice) and the All Blacks.
Botha has been troubled with a calf, ankle and achilles for some time. He has not played this international season because of injury and his absence will be felt against the physical All Blacks.
De Villiers, though, is a massive blow to the creativity of the back division.
Joe van Niekerk, Breyton Paulse, Danie Coetzee and Bryan Habana were all given fitness clearances to get on the plane to Australia on Thursday.
The Bok management had not confirmed the replacements for De Villiers and Botha but two additions to the squad would be named in the next 12 hours.
The Boks are already without Schalk Burger. To lose the likes of De Villiers and Botha could prove devastating.